1. Field of the Invention
This invention relates generally to the field of electromagnetic linear actuators and, more particularly, to a reciprocating actuator employing a permanent magnet armature which is driven by magnetic repulsion, rather than magnetic attraction.
2. Description of the Prior Art
Linear motors of the positioning type and employing permanent magnet armatures are known; see U.S. Pat. No. 3,135,880. Also known are electromagnetic linear actuators for print wires, but such actuators employ ferromagnetic armatures which are driven by magnetic attraction against the force of a restoring spring which returns the armature to a rest position after a printing operation; see U.S. Pat. Nos. 3,850,278 and 3,755,700; such actuators require a relatively large electromagnetic tractive force in order to overcome the increasing resistive force of the spring as the print wire approaches the printing medium; furthermore, the armature of such actuators is subject to bouncing when it is returned to its rest position by the force of the restoring spring.